diff --git a/ebml/EbmlCrc32.h b/ebml/EbmlCrc32.h
index 5b22302..9e3a3dc 100644
--- a/ebml/EbmlCrc32.h
+++ b/ebml/EbmlCrc32.h
@@ -54,9 +54,8 @@ const uint32 CRC32_NEGL = 0xffffffffL;
 # define CRC32_SHIFTED(c) (c >> 8)
 #endif
 
-class EBML_DLL_API EbmlCrc32 : public EbmlBinary {
+DECLARE_EBML_BINARY(EbmlCrc32)
 	public:
-		EbmlCrc32();
 		EbmlCrc32(const EbmlCrc32 & ElementToClone);
 		bool ValidateSize() const {return (GetSize() == 4);}
 		filepos_t RenderData(IOCallback & output, bool bForceRender, bool bKeepIntact = false);
diff --git a/ebml/EbmlElement.h b/ebml/EbmlElement.h
index d1ecc2f..5d229e1 100644
--- a/ebml/EbmlElement.h
+++ b/ebml/EbmlElement.h
@@ -97,6 +97,30 @@ extern const EbmlSemanticContext Context_EbmlGlobal;
     const EbmlId Id_##x    (id, idl); \
     const EbmlSemanticContext Context_##x = EbmlSemanticContext(0, NULL, &Context_##parent, global, &EBML_INFO(x)); \
     const EbmlCallbacks x::ClassInfos(x::Create, Id_##x, name, Context_##x); \
+    x::x() {}
+
+#define DEFINE_xxx_CLASS_CUS(x,id,idl,parent,name,global) \
+    const EbmlId Id_##x    (id, idl); \
+    const EbmlSemanticContext Context_##x = EbmlSemanticContext(0, NULL, &Context_##parent, global, &EBML_INFO(x)); \
+    const EbmlCallbacks x::ClassInfos(x::Create, Id_##x, name, Context_##x);
+
+#define DEFINE_xxx_UINTEGER_DEF(x,id,idl,parent,name,global,defval) \
+    const EbmlId Id_##x    (id, idl); \
+    const EbmlSemanticContext Context_##x = EbmlSemanticContext(0, NULL, &Context_##parent, global, &EBML_INFO(x)); \
+    const EbmlCallbacks x::ClassInfos(x::Create, Id_##x, name, Context_##x); \
+    x::x() :EbmlUInteger(defval) {}
+
+#define DEFINE_xxx_STRING_DEF(x,id,idl,parent,name,global,defval) \
+    const EbmlId Id_##x    (id, idl); \
+    const EbmlSemanticContext Context_##x = EbmlSemanticContext(0, NULL, &Context_##parent, global, &EBML_INFO(x)); \
+    const EbmlCallbacks x::ClassInfos(x::Create, Id_##x, name, Context_##x); \
+    x::x() :EbmlString(defval) {}
+
+#define DEFINE_xxx_FLOAT_DEF(x,id,idl,parent,name,global,defval) \
+    const EbmlId Id_##x    (id, idl); \
+    const EbmlSemanticContext Context_##x = EbmlSemanticContext(0, NULL, &Context_##parent, global, &EBML_INFO(x)); \
+    const EbmlCallbacks x::ClassInfos(x::Create, Id_##x, name, Context_##x); \
+    x::x() :EbmlFloat(defval) {}
 
 #define DEFINE_xxx_CLASS_GLOBAL(x,id,idl,name,global) \
     const EbmlId Id_##x    (id, idl); \
@@ -107,13 +131,27 @@ extern const EbmlSemanticContext Context_EbmlGlobal;
     const EbmlSemanticContext Context_##x = EbmlSemanticContext(0, NULL, NULL, global, &EBML_INFO(x)); \
     const EbmlCallbacks x::ClassInfos(x::Create, Id_##x, name, Context_##x); \
 
-#define DEFINE_EBML_CONTEXT(x)                         DEFINE_xxx_CONTEXT(x,*GetEbmlGlobal_Context)
-#define DEFINE_EBML_MASTER(x,id,idl,parent,name)       DEFINE_xxx_MASTER(x,id,idl,parent,name,*GetEbmlGlobal_Context)
-#define DEFINE_EBML_MASTER_ORPHAN(x,id,idl,name)       DEFINE_xxx_MASTER_ORPHAN(x,id,idl,name,*GetEbmlGlobal_Context)
-#define DEFINE_EBML_CLASS(x,id,idl,parent,name)        DEFINE_xxx_CLASS(x,id,idl,parent,name,*GetEbmlGlobal_Context)
-#define DEFINE_EBML_CLASS_GLOBAL(x,id,idl,name)        DEFINE_xxx_CLASS_GLOBAL(x,id,idl,name,*GetEbmlGlobal_Context)
-#define DEFINE_EBML_CLASS_ORPHAN(x,id,idl,name)        DEFINE_xxx_CLASS_ORPHAN(x,id,idl,name,*GetEbmlGlobal_Context)
+#define DEFINE_EBML_CONTEXT(x)                             DEFINE_xxx_CONTEXT(x,*GetEbmlGlobal_Context)
+#define DEFINE_EBML_MASTER(x,id,idl,parent,name)           DEFINE_xxx_MASTER(x,id,idl,parent,name,*GetEbmlGlobal_Context)
+#define DEFINE_EBML_MASTER_ORPHAN(x,id,idl,name)           DEFINE_xxx_MASTER_ORPHAN(x,id,idl,name,*GetEbmlGlobal_Context)
+#define DEFINE_EBML_CLASS(x,id,idl,parent,name)            DEFINE_xxx_CLASS(x,id,idl,parent,name,*GetEbmlGlobal_Context)
+#define DEFINE_EBML_CLASS_GLOBAL(x,id,idl,name)            DEFINE_xxx_CLASS_GLOBAL(x,id,idl,name,*GetEbmlGlobal_Context)
+#define DEFINE_EBML_CLASS_ORPHAN(x,id,idl,name)            DEFINE_xxx_CLASS_ORPHAN(x,id,idl,name,*GetEbmlGlobal_Context)
+#define DEFINE_EBML_UINTEGER_DEF(x,id,idl,parent,name,val) DEFINE_xxx_UINTEGER_DEF(x,id,idl,parent,name,*GetEbmlGlobal_Context,val)
+#define DEFINE_EBML_STRING_DEF(x,id,idl,parent,name,val)   DEFINE_xxx_STRING_DEF(x,id,idl,parent,name,*GetEbmlGlobal_Context,val)
 
+#define DECLARE_EBML_MASTER(x)  class EBML_DLL_API x : public EbmlMaster { \
+  public: \
+    x();
+#define DECLARE_EBML_UINTEGER(x)  class EBML_DLL_API x : public EbmlUInteger { \
+  public: \
+    x();
+#define DECLARE_EBML_STRING(x)    class EBML_DLL_API x : public EbmlString { \
+  public: \
+    x();
+#define DECLARE_EBML_BINARY(x)    class EBML_DLL_API x : public EbmlBinary { \
+  public: \
+    x();
 
 #if defined(EBML_STRICT_API)
 #define EBML_CONCRETE_CLASS(Type) \
diff --git a/ebml/EbmlHead.h b/ebml/EbmlHead.h
index 9e6af48..cbe9186 100644
--- a/ebml/EbmlHead.h
+++ b/ebml/EbmlHead.h
@@ -41,9 +41,8 @@
 
 START_LIBEBML_NAMESPACE
 
-class EBML_DLL_API EbmlHead : public EbmlMaster {
+DECLARE_EBML_MASTER(EbmlHead)
 	public:
-		EbmlHead();
 		EbmlHead(const EbmlHead & ElementToClone) : EbmlMaster(ElementToClone) {}
 
         EBML_CONCRETE_CLASS(EbmlHead)
diff --git a/ebml/EbmlSubHead.h b/ebml/EbmlSubHead.h
index 0615b42..f842f2c 100644
--- a/ebml/EbmlSubHead.h
+++ b/ebml/EbmlSubHead.h
@@ -43,57 +43,50 @@
 
 START_LIBEBML_NAMESPACE
 
-class EBML_DLL_API EVersion : public EbmlUInteger {
+DECLARE_EBML_UINTEGER(EVersion)
 	public:
-		EVersion() :EbmlUInteger(1) {}
 		EVersion(const EVersion & ElementToClone) : EbmlUInteger(ElementToClone) {}
 
         EBML_CONCRETE_CLASS(EVersion)
 };
 
-class EBML_DLL_API EReadVersion : public EbmlUInteger {
+DECLARE_EBML_UINTEGER(EReadVersion)
 	public:
-		EReadVersion() :EbmlUInteger(1) {}
 		EReadVersion(const EReadVersion & ElementToClone) : EbmlUInteger(ElementToClone) {}
 
         EBML_CONCRETE_CLASS(EReadVersion)
 };
 
-class EBML_DLL_API EMaxIdLength : public EbmlUInteger {
+DECLARE_EBML_UINTEGER(EMaxIdLength)
 	public:
-		EMaxIdLength() :EbmlUInteger(4) {}
 		EMaxIdLength(const EMaxIdLength & ElementToClone) : EbmlUInteger(ElementToClone) {}
 
         EBML_CONCRETE_CLASS(EMaxIdLength)
 };
 
-class EBML_DLL_API EMaxSizeLength : public EbmlUInteger {
+DECLARE_EBML_UINTEGER(EMaxSizeLength)
 	public:
-		EMaxSizeLength() :EbmlUInteger(8) {}
 		EMaxSizeLength(const EMaxSizeLength & ElementToClone) : EbmlUInteger(ElementToClone) {}
 
         EBML_CONCRETE_CLASS(EMaxSizeLength)
 };
 
-class EBML_DLL_API EDocType : public EbmlString {
+DECLARE_EBML_STRING(EDocType)
 	public:
-		EDocType() {}
 		EDocType(const EDocType & ElementToClone) : EbmlString(ElementToClone) {}
 
         EBML_CONCRETE_CLASS(EDocType)
 };
 
-class EBML_DLL_API EDocTypeVersion : public EbmlUInteger {
+DECLARE_EBML_UINTEGER(EDocTypeVersion)
 	public:
-		EDocTypeVersion() {}
 		EDocTypeVersion(const EDocTypeVersion & ElementToClone) : EbmlUInteger(ElementToClone) {}
 
         EBML_CONCRETE_CLASS(EDocTypeVersion)
 };
 
-class EBML_DLL_API EDocTypeReadVersion : public EbmlUInteger {
+DECLARE_EBML_UINTEGER(EDocTypeReadVersion)
 	public:
-		EDocTypeReadVersion() {}
 		EDocTypeReadVersion(const EDocTypeReadVersion & ElementToClone) : EbmlUInteger(ElementToClone) {}
 
         EBML_CONCRETE_CLASS(EDocTypeReadVersion)
diff --git a/ebml/EbmlVoid.h b/ebml/EbmlVoid.h
index 0d59f03..4c2745a 100644
--- a/ebml/EbmlVoid.h
+++ b/ebml/EbmlVoid.h
@@ -41,9 +41,8 @@
 
 START_LIBEBML_NAMESPACE
 
-class EBML_DLL_API EbmlVoid : public EbmlBinary {
+DECLARE_EBML_BINARY(EbmlVoid)
 	public:
-		EbmlVoid();
 		EbmlVoid(const EbmlVoid & ElementToClone) :EbmlBinary(ElementToClone){}
 		bool ValidateSize() const {return true;} // any void element is accepted
 
diff --git a/src/EbmlSubHead.cpp b/src/EbmlSubHead.cpp
index 48adb69..f642434 100644
--- a/src/EbmlSubHead.cpp
+++ b/src/EbmlSubHead.cpp
@@ -38,12 +38,12 @@
 
 START_LIBEBML_NAMESPACE
 
-DEFINE_EBML_CLASS(EVersion,            0x4286, 2, EbmlHead, "EBMLVersion");
-DEFINE_EBML_CLASS(EReadVersion,        0x42F7, 2, EbmlHead, "EBMLReadVersion");
-DEFINE_EBML_CLASS(EMaxIdLength,        0x42F2, 2, EbmlHead, "EBMLMaxIdLength");
-DEFINE_EBML_CLASS(EMaxSizeLength,      0x42F3, 2, EbmlHead, "EBMLMaxSizeLength");
-DEFINE_EBML_CLASS(EDocType,            0x4282, 2, EbmlHead, "EBMLDocType");
-DEFINE_EBML_CLASS(EDocTypeVersion,     0x4287, 2, EbmlHead, "EBMLDocTypeVersion");
-DEFINE_EBML_CLASS(EDocTypeReadVersion, 0x4285, 2, EbmlHead, "EBMLDocTypeReadVersion");
+DEFINE_EBML_UINTEGER_DEF(EVersion,            0x4286, 2, EbmlHead, "EBMLVersion", 1);
+DEFINE_EBML_UINTEGER_DEF(EReadVersion,        0x42F7, 2, EbmlHead, "EBMLReadVersion", 1);
+DEFINE_EBML_UINTEGER_DEF(EMaxIdLength,        0x42F2, 2, EbmlHead, "EBMLMaxIdLength", 4);
+DEFINE_EBML_UINTEGER_DEF(EMaxSizeLength,      0x42F3, 2, EbmlHead, "EBMLMaxSizeLength", 8);
+DEFINE_EBML_STRING_DEF  (EDocType,            0x4282, 2, EbmlHead, "EBMLDocType", "matroska");
+DEFINE_EBML_UINTEGER_DEF(EDocTypeVersion,     0x4287, 2, EbmlHead, "EBMLDocTypeVersion", 1);
+DEFINE_EBML_UINTEGER_DEF(EDocTypeReadVersion, 0x4285, 2, EbmlHead, "EBMLDocTypeReadVersion", 1);
 
 END_LIBEBML_NAMESPACE